Free throw follows binomial distribution.
probability of making free throw = probability of success = 0.5 = p
probability of fail = 1-0.5 = 0.5 = q
Binomial distribution is given by,
P(X) = [tex]^nC_{x} p^{x} q^{n-x} [/tex]
where n=11, x=5
Therefore,
P(X=5) = [tex]^(11)C_{5} (0.5)^{5} (0.5)^{11-5} [/tex] = 0.2255